An conceptual HMI controller can be thought of as a graphical user interface (GUI) with a DC motor attached to it. A web page using appropriate pushbuttons for turning on and off a DC motor would be displayed on the screen. Pressing either of the buttons will allow the DC motor to turn on or off. The following is a concept drawing of an HMI controller:

The HMI controller block diagram is an engineering development tool used to convey a complete product design using graphics. The block diagram also makes it easier to plan the breadboard for prototyping and testing of the HMI controller in a maker's workshop or laboratory bench. A final observation of the HMI controller block diagram is that the basic computer convention of inputs is on the left-hand side, the processor is located in the middle, and the outputs are placed on the right-hand side of the design layout. As shown, the desktop PC or notebook computer with the HMI GUI and pushbutton switch is on the...